proton ##ation of the en ##olate is sometimes not stereo ##sel ##ect ##ive , meaning that products can be formed as mixture ##s of ep ##ime ##rs . = = modern variants = = the short ##coming ##s noted above limit the useful ##ness of the na ##zar ##ov cy ##cl ##ization reaction in its canonical form . however , modifications to the reaction focused on remedy ##ing its issues continue to be an active area of academic research . in particular , the research has focused on a few key areas : rendering the reaction catalytic in the promoter , effect ##ing the reaction with more mild promoters to improve functional group tolerance , directing the reg ##ios ##ele ##ct ##ivity of the elimination step , and
protonation of the enolate is sometimes not stereoselective, meaning that products can be formed as mixtures of epimers. = = modern variants = = the shortcomings noted above limit the usefulness of the nazarov cyclization reaction in its canonical form. however, modifications to the reaction focused on remedying its issues continue to be an active area of academic research. in particular, the research has focused on a few key areas : rendering the reaction catalytic in the promoter, effecting the reaction with more mild promoters to improve functional group tolerance, directing the regioselectivity of the elimination step, and